The invention relates to improvements in earth moving equipment, and more particularly to a tractor with a trencher and the trencher constructed so as to be essentially self-supporting and accommodate earth moving equipment on the front of the tractor and movement of the tractor in an arcuate path and forward and backward without supporting the trencher on the tractor.
In earth moving handling and excavating equipment, one form of machine is a trencher which can be drawn forwardly and powered by a tractor. The trencher operates to dig a narrow trench of controllable depth for laying wire, piping and other underground equipment into the trench. After the trench is dug, the earth which is removed and is placed back in the trench to cover up the equipment. It is particularly advantageous if the same equipment can be used for closing the trench, such as the tractor which draws the trencher having a shovel or blade on the front to close the trench. In such operation it is necessary that the tractor be readily maneuverable so that it can be backed and turned in arcs to accurately direct the tractor and move the earth.
Power equipment must be utilized for operating the trencher which normally has a pivotal boom extending rearwardly with an endless chain on the boom and blades on the chain for digging the earth from the trench. Power for operating the chain and blades may be obtained from a prime mover on the trencher or from the power takeoff of the tractor. Power is also required for moving the trencher and tractor forwardly at a controlled slow rate. One factor which must be met by the equipment is that the relatively heavy weight of the trencher must be supported and this frequently and commonly is accomplished by supporting the trencher on the hydraulic lifted support arms on the tractor. Disadvantages are encountered in this in that the trencher is relatively heavy and a downward pulling force is encountered while the trencher is in operation in the ground which in many cases causes excessive stress on the tractor and requires that the hitch be so balanced that the front end of the tractor is not lifted off the ground. Attempts have been made to compensate for these problems, and for example U.S. Pat. No. 4,483,084 employs supporting wheels on the trencher. In the structure disclosed in this patent, the wheels are constructed such that they are driven in a forward direction and apply the forward driving force to both the tractor and trencher during operation. However, in addition to the limitations induced by this requirement, because of the necessity of a relatively rigid connection between the tractor and the trencher, the tractor can be only driven straight forward and not in an arcuate path. Also, the tractor can only be backed very carefully and the relative inflexibility of the structure makes it very difficult, if not impossible, to utilize the tractor with a blade or shovel on the front for closing the trench without having to go through the time consuming steps of unhitching and disconnecting the trencher from the tractor.
It is accordingly an object of the present invention to provide an improved trencher construction in combination with a tractor and an earth moving unit on the front wherein greater flexibility and capability is afforded than in structures heretofore available so that the tractor can be employed for closing the trenches and can be driven in an arcuate path and backed up without disconnecting the trencher.
A further object of the invention is to provide an improved trencher construction wherein supporting apparatus is provided for the trencher eliminating the need for a full support from the tractor and eliminating the hazards which occur in the unbalance created on a tractor due to the weight of the trencher and the operating forces encountered in the trencher which are transmitted to the tractor.
A still further object of the invention is to provide a trencher construction with a self-supporting wheel arrangement wherein the forces generated from the trencher due to the trencher weight and due to the forces of the trencher digging in the ground augment the weight distribution and operation of the tractor.